1. Field of the Invention
The present invention relates to a rotary printing press having a multiple-printing unit which includes printing devices arranged vertically in layers and which can print on a plurality of paper webs.
2. Description of the Related Arts
A conventional multiple-printing unit configured such that a plurality of printing devices are arranged vertically in layers is disclosed in, for example, Japanese Patent Publication (kokoku) No. H07-73908 as a multicolor printing apparatus of small installation area. In conjunction with an increase in multicolor-printed newspaper pages, such a multicolor printing apparatus has come into wide use in the field of newspaper printing.
The printing apparatus disclosed in Japanese Patent Publication (kokoku) No. H07-73908 is configured such that four printing devices are arranged vertically in layers. Each of the four printing devices includes two combinations of a plate cylinder and a blanket cylinder. The two blanket cylinders are disposed in such a manner as to be able to come into contact with each other. Thus, each of the printing devices can simultaneously print images borne on the plate cylinders onto the opposite sides of a paper web via the corresponding blanket surfaces. A paper web is sequentially threaded between the blanket cylinders of the four printing devices, whereby images in four colors are printed in a superposed manner on the opposite sides of the paper web.
The above-mentioned printing apparatus can simultaneously print on two or more paper webs by means of a single multiple-printing unit, for example, as follows. A single paper web is threaded through at least a single printing device of the four printing devices, while another paper web is threaded through at least a single printing device among the remaining printing devices.
Meanwhile, in order to simultaneously print on two or more paper webs by means of a single multiple-printing unit, two or more paper webs must be simultaneously fed to the multiple-printing unit. A rotary printing press-having a structure for such simultaneous feed of paper webs is disclosed in, for example, Japanese Patent Publication (kokoku) No. H08-451, Japanese Patent No. 2577309, and Japanese Patent Application Laid-Open (kokai) No. H10-296946.
Each of the rotary printing presses disclosed in Japanese Patent Publication (kokoku) No. H08-451, Japanese Patent No. 2577309, and Japanese Patent Application Laid-Open (kokai) No. H10-296946 includes a plurality of multiple-printing units, a single folding machine, and a plurality of web feed units. Each of the multiple-printing units is configured such that a plurality of printing devices are arranged vertically in layers. The folding machine is provided at the same level as the multiple-printing units and is adapted to superpose paper webs which have undergone printing in the multiple-printing units, to cut the superposed paper webs, and to fold resultant printed sheets. The web feed units are provided underneath the multiple-printing units and the folding machine in a number of at least two times the number of multiple-printing units. Two or more paper webs are fed to each of the multiple-printing units, whereby each of the multiple-printing units can simultaneously print on the paper webs.
In the rotary printing press disclosed in Japanese Patent Publication (kokoku) No. H08-451, a web roll support apparatus includes a web feed unit capable of supporting a web roll such that the axis of the web roll is in parallel with a row of multiple-printing units. Also, structures each having two mutually adjacent web feed units corresponding to a single multiple-printing unit are arranged along the row of multiple-printing units.
In the rotary printing press disclosed in Japanese Patent No. 2577309, a web roll support apparatus includes a web feed unit capable of supporting a web roll such that the axis of the web roll is perpendicular to a row of multiple-printing units. Also, structures each having two vertically arranged web feed units corresponding to a single multiple-printing unit are arranged along the row of multiple-printing units.
Japanese Patent Application Laid-Open (kokai) No. H10-296946 does not specifically illustrate a web feed unit of the disclosed rotary printing press. However, FIG. 1 of the publication shows a web roll support apparatus similar to that of the rotary printing press disclosed in Japanese Patent No. 2577309.
In the rotary printing press disclosed in Japanese Patent Publication (kokoku) No. H08-451, a web roll transport path for a web roll transport device for transporting a web roll to be supported by the web roll support apparatus must be provided for each of the two web feed units corresponding to a single multiple-printing unit. In order to provide web roll transport paths at the opposite sides of a row of structures each having two mutually adjacent web feed units, the corresponding planar spaces are required. Therefore, a large planar installation space is required. Additionally, two rows of web roll transport path mechanisms are required. Thus, equipment cost and maintenance cost increase.
In the rotary printing press disclosed in Japanese Patent No. 2577309, the web roll transport path for transporting a web roll to be supported by the web roll support apparatus must be provided for each structure having two vertically arranged web feed units corresponding to a single multiple-printing unit. Alternatively, a single web roll transport path must be provided for every two adjacent structures. Additionally, at least a single web roll transport path into which these web roll transport paths merge must be provided. Thus, the web roll transport path configuration is complicated, thereby increasing equipment cost and maintenance cost.
In view of similarity in the structure of the web roll support apparatus, it cannot be denied that the rotary printing press disclosed in Japanese Patent Application Laid-Open (kokai) No. H10-296946 involves a problem similar to that involved in the rotary printing press disclosed in Japanese Patent No. 2577309.
As mentioned previously, a multiple-printing unit having printing devices arranged vertically in layers originally uses different inks for the individual printing devices, thereby performing multicolor printing by use of as many inks as printing devices arranged vertically in layers. Therefore, it is highly improbable that a rotary printing press having a plurality of multiple-printing units is operated in such a manner that printing operation is performed, while a plurality of paper webs are threaded through all of the multiple-printing units.
Therefore, in the case of the rotary printing apparatus disclosed in Japanese Patent Publication (kokoku) No. H08-451, Japanese Patent No. 2577309, and Japanese Patent Application Laid-Open (kokai) No. H10-296946, which are configured such that two web feed units are provided for each of the multiple-printing units, one or more web feed units become idle during printing. Provision of such web feed units is wasteful, and even such idle web feed units require maintenance, thereby incurring additional maintenance materials and labor.
An object of the present invention is to provide a rotary printing press in which a plurality of printing units including at least one multiple-printing unit having a plurality of printing devices arranged vertically in layers with plate cylinders of the printing devices arranged in parallel with one another are arranged in a row and which includes, in addition to a first web feed unit, a second web feed unit corresponding to the multiple-printing unit so as to allow the multiple-printing unit to print on a plurality of paper webs, wherein a web roll transport path for feeding a web roll to each of the two web feed units corresponding to a single multiple-printing unit is provided in a minimal planar space in a simple, shortest-route arrangement involving low equipment and maintenance costs.
Another object of the present invention is to provide a rotary printing press in which the web roll transport path is provided in a minimal planar space in a simple, shortest-route arrangement, which can avoid the wasteful provision of second web feed units, in one-to-one correspondence, for all of the multiple-printing units, and which can feed paper webs from the first and second web feed units to a desired multiple-printing unit so as to perform printing on both the paper webs.
A rotary printing press according to the present invention comprises at least one folding unit, and a plurality of printing units arranged in a row together with the folding unit. The printing unit includes at least one multiple-printing unit having a plurality of printing devices arranged vertically in layers with printing cylinders of the printing devices arranged in parallel with one another. The printing press comprises a plurality of first web feed units provided for the printing units in one-to-one correspondence, and at least one second web feed unit provided in such a manner as to form a counterpart to the first web feed unit corresponding to the multiple-printing unit. Each of the first and second web feed units includes at least one web roll support device capable of supporting a web roll with an axis of the web roll extending in parallel with the row of printing units. The printing press further comprises a web roll transport apparatus, which comprises a web roll transport path provided in between the first web feed units and the second web feed unit and along the row of printing units, and a web roll transport device traveling along the web roll transport path. A plurality of web roll exchange stations are provided for the first web feed units and the second web feed unit in one-to-one correspondence and in such a manner as to face the web roll transport path.
According to the above configuration, the web roll transport path for feeding a web roll to each of the two web feed units corresponding to a single multiple-printing unit can be provided in a minimal planar space in a simple, shortest-route arrangement. Thus, as compared with a conventional similar rotary printing press, equipment and maintenance costs of the web roll transport path can be reduced.
When the printing units include a plurality of multiple-printing units, preferably, the second web feed unit is provided in such a manner as to be movable along a web feed unit travel path provided in parallel with the web roll transport path and in such a manner as to be able to be stopped and positioned at predetermined stop positions corresponding to the multiple-printing units, and the web roll exchange station for the second web feed unit is provided at each of the stop positions.
According to the above configuration, in individual printing operations, a multiple-printing unit for printing on two paper webs that requires the second web feed unit is selected according to the pattern of superposition of printed paper webs, and the second web feed unit can be moved to the position corresponding to the multiple-printing unit that requires the second web feed unit. Thus, the above configuration can avoid the wasteful provision in one-to-one correspondence of second web feed units for all of the multiple-printing units as well as the wasteful provision of a special threading path for superposing printed paper webs in a required order, thereby enhancing work efficiency through simplification of threading and reducing the burden of maintenance work for the threading path.
In the rotary printing press having the above-described structure, before printing is started, a multiple-printing unit(s) for printing on a single paper web and a multiple-printing unit(s) for printing on two paper webs are determined, and threading for these multiple-printing units is performed as follows. In the multiple-printing unit for printing on a single paper web, a paper web from the first web feed unit is sequentially threaded through required printing devices among those arranged vertically in layers. In the multiple-printing unit for printing on two paper webs, paper webs from the first and second web feed units are sequentially threaded through required printing devices among those arranged vertically in layers. Subsequently, the paper webs are further threaded up to a folding unit such that the paper webs are superposed in a required order before reaching the folding unit. After completion of threading, the rotary printing press is operated, thereby producing a printed material consisting of printed sheets which are printed by the corresponding printing units and superposed in a required order.
In supply of a web roll to each web feed unit, a web roll is loaded onto the web roll transport device. Then, the loaded web roll transport device is caused to travel along the web roll transport path, provided on one side of the first web feed units to extend along the row of printing units, to a corresponding web roll exchange station provided in such a manner as to face the web roll transport path. In the web roll exchange station, the web roll is transferred from the web roll transport device to the web roll support device of the web feed unit to thereby be supported by the web roll support device.
In the case where the second web feed unit is movable along the web feed unit travel path, first, the second web feed unit is moved along the web feed unit travel path provided in parallel with the web roll transport path and is then stopped and positioned at a stop position corresponding to a multiple-printing unit which is adapted to print on two paper webs and is preselected in view of superposition of printed paper webs.
Subsequently, a paper web from the first web feed unit is threaded through a multiple-printing unit for printing on a single paper web in such a manner as to be sequentially threaded through required printing devices among those arranged vertically in layers. Also, paper webs from the first and second web feed units are threaded through a multiple-printing unit for printing on two paper webs in such a manner as to be sequentially threaded through required printing devices among those arranged vertically in layers. Then, the paper webs are further threaded up to the folding unit such that the paper webs are superposed in a required order before reaching the folding unit. After completion of threading, the rotary printing press is operated, thereby producing a printed material consisting of printed sheets which are printed by the corresponding printing units and superposed in a required order.
In supply of a web roll to each web feed unit, a web roll is loaded onto the web roll transport device. Then, the loaded web roll transport device is caused to travel along the web roll transport path, provided on one side of the first web feed units to extend along the row of printing units and along side portions, to a corresponding web roll exchange station provided in such a manner as to face the web roll transport path. In the web roll exchange station, the web roll is transferred from the web roll transport device to the web roll support device of the web feed unit to thereby be supported by the web roll support device.